BackgroundAn endangered species is in immediate danger of extinction, or of disappearing from the earth forever. A threatened species will likely become endangered if steps are not taken to protect it. The mountain gorilla is one of thousands of species around the world at risk of becoming extinct and in desperate need of protection. In the United States alone, more than 1,200 wildlife, fish, and plant species are considered threatened or endangered.

While species have evolved and disappeared throughout time, experts warn that today's rate of extinction is alarmingly high. Scientists say that it is natural to lose one species every 100 years. Yet North America has lost more than 500 species since 1620. The National Wildlife Federation, an organization that encourages Americans to protect wildlife, estimates that today nearly twenty plant and animal species around the world are lost every hour.

A habitat is the place where an animal or plant lives that includes essential things for its survival—food, water, shelter, and space. Habitat loss is the main reason a species can become endangered or threatened. Other causes include the over-killing and over-collection of animals and plants for food or trade, the introduction of nonnative plants and animals to environments, pollution, and disease. Humans are changing the air, water, and land faster than species can adapt. When the changes are too severe, they cannot survive.

Why is it important to protect endangered and threatened species? The U.S. Congress answered this question in the Endangered Species Act of 1973, which helps protect threatened and endangered animals and plants. The introduction of the law states that endangered and threatened species "are of esthetic, ecological, educational, historical, recreational, and scientific value to the Nation and its people." More than 1,200 U.S. species and more than 500 international ones—including Africa's mountain gorilla—are protected under the Act. The Endangered Species Act has been 99 percent effective in preventing the extinction of listed species. The International Union for Conservation of Nature (IUCN) includes thousands of other endangered and vulnerable species from around the world and identifies their threats on its annual Red List of Threatened Species.

Plants and animals are part of ecosystems—communities of living things and their environments that interact and are linked together. Losing one species can greatly disturb the balance within an ecosystem and trigger the loss of several other species. According to the U.S. Fish & Wildlife Service, a government agency that works to save America’s plant and animal species from extinction, the loss of one plant species can cause the disappearance of up to thirty others. About 40 percent of today’s medicines, used to treat illnesses from heart disease to cancer, comes from plants or animals. If the mountain gorillas’ habitat in the Virunga Mountains is destroyed, countless other animal and plant life will also lose their home and be at risk of dying out.

Extinction leads to a decline in biodiversity—the number and variety of different living things and the ecosystems that they form. It results in less variety of life on Earth, leaving humans with fewer resources, and even harming the air that we breathe, water that we drink, and soil that we need to grow nutritious food.

By raising awareness of the threats to the world’s animals and plants, and by starting projects to protect them, you and your students will help preserve Earth’s biodiversity. Procedure1. Distribute or display pictures of endangered or threatened species. Visit the IUCN Red List Photo Gallery for several examples: www.iucn.org/ . The Endangered Species Project has others at: www.endangeredspecies.org/ . For pictures of the endangered mountain gorilla, visit www.scholastic.com/mizagorilla .

2. Explain that the animals pictured are either endangered or threatened. Share with students the definitions of these terms from the background section. Ask: What would the planet be like without a variety of plant and animal life? What are the main threats facing the mountain gorilla and many other types of animals? (Answers may include: habitat loss, hunting, introduction of nonnative plants, pollution, disease, and climate change.)

3. Download and distribute Section 2 of the U.S. Endangered Species Act of 1973, as found here: www.fws.gov/endangered/ESA/sec2.html . Explain that Congress passed the law to protect threatened and endangered animals and plants and their environments in the U.S. and in other countries. More than 1,200 U.S. species and more than 500 international ones—including Africa’s mountain gorilla—are protected under the Act. Have a student volunteer read section 2 number 3, which states that listed species of fish, wildlife, and plants "are of esthetic, ecological, educational, historical, recreational, and scientific value to the Nation and its people." Ask students to share what they think each term means and how it may relate to the value of protecting a species. Have students consider the bald eagle, one of many animals that have benefited from the Act.

4. Continue to discuss the many ways in which animals and plants support human life (they provide food; medicine; clean air, water, and soil; recreational activities). Ask students to think about how living things are part of the "web of life"—how they are connected and interact in their ecosystems. Have students define the term ecosystem and provide examples. Refer to the background section to discuss how the loss of one species can greatly disrupt the balance and function of an ecosystem and ultimately lead to less variety of plant and animal life on Earth.

7. Have student groups share their completed charts. Discuss that efforts to protect endangered species are successful. For example, the Endangered Species Act has been 99 percent effective in preventing the extinction of listed species. Lead students to think about what things they can do as a class or school to work toward a solution to protect Africa’s mountain gorillas and other endangered or threatened species.